Apparatus for autonomously controlling the inflow of production fluids from a subterranean well

ABSTRACT

A flow control apparatus ( 100 ) for controlling the inflow of production fluids ( 134, 140 ) from a subterranean well includes a tubular member ( 118 ) having at least one opening ( 138 ) that allows fluid flow between an exterior of the tubular member ( 118 ) and an interior flow path of the tubular member ( 118 ) and a flow restricting device ( 120 ) operably positioned in a fluid flow path between a fluid source and the at least one opening ( 138 ). The flow restricting device ( 120 ) includes a valve ( 128, 130 ) and an actuator ( 126 ). The actuator ( 126 ) includes a material that swells in response to contact with an undesired fluid ( 140 ), such as water or gas. The flow restricting device ( 120 ) is operable to autonomously reduce the fluid flow through the flow control apparatus ( 100 ) in response to contact between the material and the undesired fluid ( 140 ).

TECHNICAL FIELD OF THE INVENTION

This invention relates, in general, to controlling the production of fluids from a well that traverses a hydrocarbon bearing subterranean formation and, in particular, to an apparatus for autonomously controlling the inflow of production fluids from the subterranean well in response to contact with an undesired fluid.

BACKGROUND OF THE INVENTION

Without limiting the scope of the present invention, its background will be described with reference to producing fluid from a subterranean formation, as an example.

During the completion of a well that traverses a hydrocarbon bearing subterranean formation, production tubing and various equipment are installed in the well to enable safe and efficient production of the formation fluids. For example, to prevent the production of particulate material from an unconsolidated or loosely consolidated subterranean formation, certain completions include one or more sand control screens positioned proximate the desired production intervals. In other completions, to control the flow rate of production fluids into the production tubing, it is common practice to install one or more flow control devices within the tubing string.

Recently, attempts have been made to utilize fluid flow control devices within completions requiring sand control. For example, in one such device, after production fluids flows through the filter media of the sand control screen, the fluids are directed into a flow control labyrinth. A slidable sleeve on the labyrinth controls the fluid velocity therethrough. The slidable sleeve is moved by a remotely and electrically-operated device placed in the sand control screen. The fluid leaving the labyrinth passes to the tubing string for carrying to the surface. While certain benefits have been achieved through the use of such devices, many of these devices are complicated to operate, have suffered from poor reliability and require certain intervention for operation.

Accordingly, need has arisen for a fluid flow control device for controlling the inflow of formation fluids in a completion requiring sand control. A need has also arisen for such a fluid flow control device that is not difficult or expensive to manufacture. Further, a need has arisen for such a fluid flow control device that is reliable in a variety of flow conditions and does not require intervention to control inflow.

SUMMARY OF THE INVENTION

The present invention disclosed herein comprises a flow control apparatus for controlling the inflow of formation fluids. The flow control apparatus of the present invention is not difficult or expensive to manufacture. In addition, the flow control apparatus of the present invention is reliable in a variety of flow conditions and does not require intervention to control inflow.

In one aspect, the present invention is directed to a flow control apparatus for controlling the inflow of production fluids from a subterranean well that includes a tubular member having at least one opening that allows fluid flow between an exterior of the tubular member and an interior flow path of the tubular member and a flow restricting device operably positioned in a fluid flow path between a fluid source and the at least one opening. The flow restricting device includes a valve and an actuator. The actuator includes a material that swells in response to contact with an undesired fluid, such as water or gas. The flow restricting device is operable to autonomously reduce the fluid flow through the flow control apparatus in response to contact between the material and the undesired fluid.

In one embodiment of the flow control apparatus, fluid flow through the flow control apparatus is increasingly restricted in response to contact between the material and the undesired fluid. In another embodiment, fluid flow through the flow control apparatus is substantially completely restricted in response to contact between the material and the undesired fluid.

In certain embodiments of the flow control apparatus, the valve includes a sliding sleeve that is operated from the open position to a choking or closed position by the actuator. In other embodiments, the valve includes a longitudinally shiftable valve element that is operated from the open position to a choking or closed position by the actuator. In still other embodiments, the valve includes a valve element having a fluid flow passageway with a cross sectional area that is reduced in response to contact between the material and the undesired fluid. In yet another embodiment, the actuator includes a biasing member that biases a valve element in a first direction. In this embodiment, the material prevents movement of the valve element in the first direction until the material is contacted by the undesired fluid.

In one embodiment of the flow control apparatus, once the material contacts the undesired fluid, the material permanently remains in a swelled state. In another embodiment of the flow control apparatus, once the material contacts the undesired fluid, the material remains in a swelled state as long as the material stays in contact with the undesired fluid but returns to an unswelled state if contact with the undesired fluid ceases.

In another aspect, the present invention is directed to a sand control screen that is positionable within a wellbore. The sand control screen includes a base pipe having at least one opening that allows fluid flow between an exterior of the base pipe and an interior flow path of the base pipe and a filter medium positioned exteriorly of the base pipe. The filter medium selectively allows fluid flow therethrough and prevents particulate flow of a predetermined size therethrough. A flow restricting device is operably positioned in a fluid flow path between the filter medium and the at least one opening. The flow restricting device including a valve and an actuator. The actuator includes a material that swells in response to contact with an undesired fluid such that the flow restricting device is operable to autonomously reduce the fluid flow through the screen in response to contact between the material and the undesired fluid.

In a further aspect, the present invention is directed to a sand control completion for installation in a wellbore. The completion includes first and second seal assemblies that define a production zone in the wellbore and a sand control screen operably positioned between the first and second seal assemblies. The sand control screen includes a base pipe having at least one opening that allows fluid flow between an exterior of the base pipe and an interior flow path of the base pipe, a filter medium positioned exteriorly of the base pipe, the filter medium selectively allowing fluid flow therethrough and preventing particulate flow of a predetermined size therethrough and a flow restricting device operably positioned in a fluid flow path between the filter medium and the at least one opening. The flow restricting device includes a valve and an actuator. The actuator includes a material that swells in response to contact with an undesired fluid such that the flow restricting device is operable to autonomously reduce the fluid flow from the production zone in response to contact between the material and the undesired fluid.

In yet another aspect, the present invention is directed to a multizone sand control completion for installation in a wellbore. The completion includes at least two sets of first and second seal assemblies that define at least two production zones in the wellbore and a sand control screen positioned between each of the first and second seal assemblies. Each of the sand control screens includes a base pipe having at least one opening that allows fluid flow between an exterior of the base pipe and an interior flow path of the base pipe, a filter medium positioned exteriorly of the base pipe, the filter medium selectively allowing fluid flow therethrough and preventing particulate flow of a predetermined size therethrough and a flow restricting device operably positioned in a fluid flow path between the filter medium and the at least one opening. Each flow restricting device includes a valve and an actuator. The actuators include a material that swells in response to contact with an undesired fluid such that each of the flow restricting devices is operable to autonomously reduce the fluid flow from the respective production zones in response to contact between the material and the undesired fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:

FIG. 1 is a schematic illustration of a well system operating a plurality of fluid flow control devices according to the present invention;

FIG. 2A is side view partially in quarter section of a fluid flow control device according to the present invention in its least restricting configuration;

FIG. 2B is side view partially in quarter section of a fluid flow control device according to the present invention in its most restricting configuration;

FIG. 3A is side view partially in quarter section of a fluid flow control device according to the present invention in its least restricting configuration;

FIG. 3B is side view partially in quarter section of a fluid flow control device according to the present invention in its most restricting configuration;

FIG. 4A is side view partially in quarter section of a fluid flow control device according to the present invention in its least restricting configuration;

FIG. 4B is side view partially in quarter section of a fluid flow control device according to the present invention in its most restricting configuration;

FIG. 5A is side view partially in quarter section of a fluid flow control device according to the present invention in its least restricting configuration;

FIG. 5B is side view partially in quarter section of a fluid flow control device according to the present invention in its most restricting configuration;

FIG. 6A is side view partially in quarter section of a fluid flow control device according to the present invention in its least restricting configuration;

FIG. 6B is side view partially in quarter section of a fluid flow control device according to the present invention in its most restricting configuration;

FIG. 7A is side view partially in quarter section of a fluid flow control device according to the present invention in its least restricting configuration;

FIG. 7B is side view partially in quarter section of a fluid flow control device according to the present invention in its most restricting configuration;

FIG. 8A is side view partially in quarter section of a fluid flow control device according to the present invention in its least restricting configuration; and

FIG. 8B is side view partially in quarter section of a fluid flow control device according to the present invention in its most restricting configuration.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the present invention.

Referring initially to FIG. 1, therein is depicted a well system including a plurality of fluid flow control devices embodying principles of the present invention that is schematically illustrated and generally designated 10. In the illustrated embodiment, a wellbore 12 extends through the various earth strata. Wellbore 12 has a substantially vertical section 14, the upper portion of which has installed therein a casing string 16. Wellbore 12 also has a substantially horizontal section 18 that extends through a hydrocarbon bearing subterranean formation 20. As illustrated, substantially horizontal section 18 of wellbore 12 is open hole.

Positioned within wellbore 12 and extending from the surface is a tubing string 22. Tubing string 22 provides a conduit for formation fluids to travel from formation 20 to the surface. Positioned within tubing string 22 are a plurality of seal assemblies 24, 26, 28, 30, 32, 34 and a plurality of fluid flow control devices 36, 38, 40, 42, 44. Each of the seal assemblies 24, 26, 28, 30, 32, 34 provides a fluid seal between tubing string 22 and the wall of wellbore 12. Each pair of seal assemblies defines a production interval. As illustrated, seal assemblies 24, 26 define production interval 46, seal assemblies 26, 28 define production interval 48, seal assemblies 28, 30 define production interval 50, seal assemblies 30, 32 define production interval 52 and seal assemblies 32, 34 define production interval 54.

Through use of the fluid flow control devices 36, 38, 40, 42, 44 of the present invention and by providing numerous production intervals 46, 48, 50, 52, 54, precise control over the volume and composition of the produced fluids is enabled. For example, in an oil production operation if an undesired fluid component, such as water or gas, is entering one of the production intervals, the fluid flow control device in that interval will autonomously restrict the production of that undesired fluid component and in some cases the entire fluid stream from that production interval. Accordingly, when a production interval corresponding to a particular one of the fluid flow control devices produces a greater proportion of an undesired fluid, the fluid flow control device in that interval will increasingly or entirely restrict flow from that interval. Thus, the other production intervals which are producing a greater proportion of desired fluid, in this case oil, will contribute more to the production stream entering tubing string 22. In particular, there will be a greater pressure drop from formation 20 to tubing string 22, resulting in a greater production of the desired fluid, due to the increased restriction to flow from the production interval that would otherwise be producing a greater proportion of the undesired fluid.

In the illustrated embodiment, each of the fluid flow control devices 36, 38, 40, 42, 44 provides not only fluid flow control capability but also sand control capability. The sand control screen elements or filter media associated with fluid flow control devices 36, 38, 40, 42, 44 are designed to allow fluids to flow therethrough but prevent particulate matter of sufficient size from flowing therethrough. The exact design of the screen element associated with fluid flow control devices 36, 38, 40, 42, 44 is not critical to the present invention as long as it is suitably designed for the characteristics of the formation fluids and any treatment operations to be performed. For example, the sand control screen may utilize a nonperforated base pipe having a wire wrapped around a plurality of ribs positioned circumferentially around the base pipe that provide stand off between the base pipe and the wire wrap. Alternatively, a fluid-porous, particulate restricting, metal material such as a plurality of layers of a wire mesh that are sintered together to form a fluid porous wire mesh screen could be used as the filter medium. As illustrated, a protective outer shroud having a plurality of perforations therethrough may be positioned around the exterior of the filter medium.

Even though FIG. 1 depicts the fluid flow control devices of the present invention in an open hole environment, it should be understood by those skilled in the art that the fluid flow control devices of the present invention are equally well suited for use in cased wells. Also, even though FIG. 1 depicts one fluid flow control device in each production interval, it should be understood by those skilled in the art that any number of fluid flow control devices of the present invention may be deployed within a production interval without departing from the principles of the present invention.

In addition, even though FIG. 1 depicts the fluid flow control devices of the present invention in a horizontal section of the wellbore, it should be understood by those skilled in the art that the fluid flow control devices of the present invention are equally well suited for use in deviated or vertical wellbores. Accordingly, it should be understood by those skilled in the art that the use of directional terms such as above, below, upper, lower, upward, downward and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure. Further, even though FIG. 1 depicts the fluid flow control devices of the present invention as including sand control screen elements, it should be understood by those skilled in the art that the fluid flow control devices of the present invention are equally well suited for use in completions that do not require sand control.

Referring next to FIGS. 2A-2B, therein is depicted a fluid flow control device according to the present invention that is representatively illustrated and generally designated 100. Fluid flow control device 100 may be suitably coupled to other similar fluid flow control devices, seal assemblies, production tubulars or other downhole tools to form a tubing string as described above. Fluid flow control device 100 includes a sand control screen section 102 and a flow restrictor section 104. Sand control screen section 102 includes a suitable sand control screen element or filter medium, such as a wire wrap screen, a woven wire mesh screen or the like, designed to allow fluids to flow therethrough but prevent particulate matter of sufficient size from flowing therethrough. In the illustrated embodiment, a protective outer shroud 106 having a plurality of perforations 108 is positioned around the exterior of the filter medium.

Flow restrictor section 104 is configured in series with sand control screen section 102 such that fluid must pass through sand control screen section 102 prior to entering flow restrictor section 104. Flow restrictor section 104 includes an outer housing 110. Outer housing 110 defines an annular chamber 112, an annular chamber 114 and an annular chamber 116 with base pipe 118. Disposed between annular chamber 112 and annular chamber 114 and partially within annular chamber 114 is a valve assembly 120. Valve assembly 120 includes a tubular fluid passageway 122, a support member 124, an actuator 126 and a sliding sleeve 128. Disposed between annular chamber 114 and annular chamber 116 is a support member 130 having a tubular fluid passageway 132.

As best seen in FIG. 2A, tubular fluid passageway 122 serves as a first stage flow restrictor to control fluid flow through fluid flow control device 100 when a desired fluid, such as oil, depicted as arrows 134, is being produced. As illustrated, once desired fluid 134 enters flow restrictor section 104, desired fluid 134 passes through annular chamber 112 and encounters tubular fluid passageway 122 which restricts the flow of desired fluid 134. After passing through tubular fluid passageway 122, desired fluid 134 enters annular chamber 114 before passing into the interior flow path of base pipe 118 via openings 136, which are depicted in the form of slots. Once inside the interior flow path of base pipe 118, desired fluid 134 flows to the surface within the tubing string. In addition, a portion of desired fluid 134 (not pictured) also passes through tubular fluid passageway 132, that serves as a second stage flow restrictor, before passing into base pipe 118 via openings 138. As tubular fluid passageway 132 provides a greater restriction to flow than openings 136, the majority of desired fluid 134 enters base pipe 118 via openings 136.

As best seen in FIG. 2B, when an undesired fluid, such as water, depicted as arrows 140, is produced, valve assembly 120 is actuated to its closed or choking position. In the illustrated embodiment, this actuation is achieved by longitudinally shifting sliding sleeve 128 into contact with support member 130 in response to the expansion of actuator 126. Once sliding sleeve 128 contacts support member 130 all or a majority of the undesired fluid 140 must now pass through tubular fluid passageway 132 before entering base pipe 118 via openings 138. As tubular fluid passageway 132 provides a greater restriction to flow than tubular fluid passageway 122, the production of undesired fluid 140 through fluid flow control device 100 is reduced as compared to the production of desired fluid 134 in FIG. 2A. The increased pressure drop caused by tubular fluid passageway 132 not only reduces the production of undesired fluid 140 from the production interval corresponding to fluid flow control device 100 but may also tend to increase production from other production intervals which are producing a desired fluid. Specifically, as there will be a greater pressure drop from the formation to the tubing string for all fluids, with a greater restriction to flow only being applied to undesired fluids, a greater production of fluids from intervals not producing the undesired fluid will occur.

As noted above, the actuation of valve assembly 120 is achieved in response to the expansion of actuator 126. More specifically, actuator 126 is formed from a material that expands when it comes in contact with an activating agent. For example, the material of actuator 126 may be a polymer that swells multiple times its initial size upon activation by an activating agent that stimulates the polymer chains to expand both radial and axially. In an autonomous implementation of fluid flow control device 100, the undesired fluid serves as the activating agent. For example, when the undesired fluid is water, the material of actuator 126 may be a water-swellable polymer such as a water-swellable elastomer or water-swellable rubber. More specifically, the material of actuator 126 may be a water-swellable hydrophobic polymer or water-swellable hydrophobic copolymer and preferably a water-swellable hydrophobic porous copolymer. As another example, the material of actuator 126 may be a salt polymer such as polyacrylamide or modified crosslinked poly(meth)acrylate that has the tendency to attract water from salt water through osmosis wherein water flows from an area of low salt concentration, the formation water, to an area of high salt concentration, the salt polymer, across a semi permeable membrane, the interface between the polymer and the production fluids, that allows water molecules to pass therethrough but prevents the passage of dissolved salts therethrough. Other embodiments of actuator 126 may employ different types of swelling polymers or materials that are activated by other activating agents. For example, in certain implementations, it may be desirable to have the material of actuator 126 swell upon activation by a hydrocarbon gas component of the production fluids.

As best seen in FIG. 2B, once actuator 126 is exposed to the activating agent, actuator 126 swells to longitudinally shift sliding sleeve 128 into contact with support member 130. Once this operation is complete, actuator 126 retains the activating fluid therein. As a result, after actuator 126 has transformed from its unswelled state (FIG. 2A) to its swelled state (FIG. 2B), actuator 126 retains its expanded size. If required, full access through fluid flow control device 100 can be reestablished via removal of plug 142. For example, plug 142 may be mechanically removed from base pipe 118 or chemically attacked such that a fluid flow path is created upstream of valve assembly 120. It should be noted that the use of plug 142 or other similar removeable device in this and the other embodiments of the present invention is an additional feature which may be included or excluded optionally. Alternatively, in certain embodiments, actuator 126 may be deactivated upon removal of the activating agent from contact with actuator 126. This implementation is useful in the scenario in which an oil producing production zone temporarily produces the unwanted fluid of water that acts as the activating agent for actuator 126, then later reverts back to oil production. In this case, actuator 126 is transitioned back from its swelled state to its unswelled state due to the removal of the activating agent.

Depended upon the specific composition of actuator 126, the swelling process may take place over a relatively short period of time, several minutes, or a relatively long period of time, several days or weeks. As flow control device 100 is typically installed in a well that contains drilling fluids, which may include the activating agent of actuator 126, a composition for the material of actuator 126 with a relatively long swelling process may be desirable to enable the installation of actuator 126 without immediate actuation of flow control device 100, thus enabling the drilling fluid to be removed from contact with actuator 126 before actuation takes place. The removal of the drilling fluids could be done by displacing the drilling fluids with other fluids form the surface of by flowing reservoir fluids through flow control device 100. Additionally or alternatively, an outer skin may be applied to actuator 126 prior to installation that protects actuator 126 from any activation agent in the drilling fluids. For example, the skin may be relatively impermeable to the activating agent such that contact between the activating agent and actuator 126 is initially limited or the skin may entirely prevent contact between the activating agent and actuator 126 until such skin is removed, for example, due to the passage of time or a treatment used to remove the skin from actuator 126.

Even though fluid flow control device 100 has been described as having one valve assembly 120, it should be understood by those skilled in the art that a fluid flow control device of the present invention could alternatively have more than one valve assembly positioned in the flow restrictor section thereof. The number of valve assemblies and the exact location and circumferential distribution of the valve assemblies will be determined based upon a number of factors including the volume of desired fluid to be produced through fluid flow control device 100, the types or types of fluid that comprise the desired fluid and undesired fluid, the mechanical space requirements within fluid flow control device 100 and the like. In addition, even though the fluid passageways 122, 132 have been described as being tubular, it should be understood by those skilled in the art that the passageways or nozzles that restrict fluid flow through fluid flow control device 100 could alternatively have different configurations including different cross sectional shapes and different directional pathways such as labyrinth type pathways, without departing from the principles of the present invention.

Referring next to FIGS. 3A-3B, therein is depicted a fluid flow control device according to the present invention that is representatively illustrated and generally designated 200. Fluid flow control device 200 includes a sand control screen section 202 and a flow restrictor section 204. Sand control screen section 202 includes a suitable sand control screen element or filter medium. In the illustrated embodiment, a protective outer shroud 206 having a plurality of perforations 208 is positioned around the exterior of the filter medium.

Flow restrictor section 204 is configured in series with sand control screen section 202 such that fluid must pass through sand control screen section 202 prior to entering flow restrictor section 204. Flow restrictor section 204 includes an outer housing 210. Outer housing 210 defines an annular chamber 212 and an annular chamber 214 with base pipe 218. Disposed at least partially within annular chamber 214 is a valve assembly 220. Valve assembly 220 includes a tubular fluid passageway 222, a support member 224, an actuator 226, a sliding sleeve 228 and a support member 230.

As best seen in FIG. 3A, tubular fluid passageway 222 serves as a flow restrictor to control fluid flow through fluid flow control device 200 when a desired fluid 234 is being produced. As illustrated, once desired fluid 234 enters flow restrictor section 204, desired fluid 234 passes through annular chamber 212 and encounters tubular fluid passageway 222 which restricts the flow of desired fluid 234. After passing through tubular fluid passageway 222, desired fluid 234 enters the interior of sliding sleeve 228, passes through openings 232 into annular chamber 214 before passing into base pipe 218 via openings 236 for transport to the surface.

As best seen in FIG. 3B, when an undesired fluid 240 is produced, valve assembly 220 is actuated to its closed or choking position. In the illustrated embodiment, this actuation is achieved by longitudinally shifting sliding sleeve 228 such that openings 232 are blocked by the outer surface of the tubular including tubular fluid passageway 222. Depending upon the sealing therebetween, this may result in a complete shut off of flow through fluid flow control device 200. In some instances a complete closedown of production is not wanted. In the illustrated embodiment an incomplete seal is created between sliding sleeve 228 and tubular fluid passageway 222. In this manner, the actuation of actuator 226 creates an increased restriction to flow, without completely preventing flow. Thus, some of unwanted fluid 240 is permitted to flow through openings 236 into base pipe 218.

Actuator 226 is formed from a material that expands when it comes in contact with an activating agent. In an autonomous implementation of fluid flow control device 200, undesired fluid 240 serves as the activating agent. As best seen in FIG. 3B, once actuator 226 is exposed to the activating agent, actuator 226 swells to longitudinally shift sliding sleeve 228. Once this operation is complete, actuator 226 retains the activating fluid therein. As a result, after actuator 226 has transformed from its unswelled state (FIG. 3A) to its swelled state (FIG. 3B), actuator 226 retains its expanded size. If required, full access through fluid flow control device 200 can be reestablished via removal of plug 242. Alternatively, in certain embodiments, actuator 226 may be deactivated upon removal of the activating agent from contact with actuator 226. Alternatively or additionally, an outer skin may be applied to actuator 226 prior to installation that protects actuator 226 from premature actuation.

Referring next to FIGS. 4A-4B, therein is depicted a fluid flow control device according to the present invention that is representatively illustrated and generally designated 300. Fluid flow control device 300 includes a sand control screen section 302 and a flow restrictor section 304. Sand control screen section 302 includes a suitable sand control screen element or filter medium. In the illustrated embodiment, a protective outer shroud 306 having a plurality of perforations 308 is positioned around the exterior of the filter medium.

Flow restrictor section 304 is configured in series with sand control screen section 302 such that fluid must pass through sand control screen section 302 prior to entering flow restrictor section 304. Flow restrictor section 304 includes an outer housing 310. Outer housing 310 defines an annular chamber 312 and an annular chamber 314 with base pipe 318. Disposed at least partially within annular chamber 314 is a valve assembly 320. Valve assembly 320 includes a tubular fluid passageway 322, a support member 324, an actuator 326 and a support member 330.

As best seen in FIG. 4A, tubular fluid passageway 322 serves as a flow restrictor to control fluid flow through fluid flow control device 300 when a desired fluid 334 is being produced. As illustrated, once desired fluid 334 enters flow restrictor section 304, desired fluid 334 passes through annular chamber 312 and encounters tubular fluid passageway 322 which restricts the flow of desired fluid 334. After passing through tubular fluid passageway 322, desired fluid 334 enters annular chamber 314 before passing into base pipe 318 via openings 336 for transport to the surface.

As best seen in FIG. 4B, when an undesired fluid 340 is produced, valve assembly 320 is actuated to its closed or choking position. In the illustrated embodiment, this actuation is achieved by longitudinally shifting the tubular that defines tubular fluid passageway 222 such that it comes in contact with support member 330. Depending upon the sealing therebetween, this may result in a complete shut off of flow through fluid flow control device 300. In some instances a complete closedown of production is not wanted. In the illustrated embodiment an incomplete seal is created between the tubular and support member 330. In this manner, the actuation of actuator 326 creates an increased restriction to flow, without completely preventing flow. Thus, some of unwanted fluid 340 is permitted to flow through openings 336 into base pipe 318.

Actuator 326 is formed from a material that expands when it comes in contact with an activating agent. In an autonomous implementation of fluid flow control device 300, undesired fluid 340 serves as the activating agent. As best seen in FIG. 4B, once actuator 326 is exposed to the activating agent, actuator 326 swells to longitudinally shift the tubular. Once this operation is complete, actuator 326 retains the activating fluid therein. As a result, after actuator 326 has transformed from its unswelled state (FIG. 4A) to its swelled state (FIG. 4B), actuator 326 retains its expanded size. If required, full access through fluid flow control device 300 can be reestablished via removal of plug 342. Alternatively, in certain embodiments, actuator 326 may be deactivated upon removal of the activating agent from contact with actuator 326. Alternatively or additionally, an outer skin may be applied to actuator 326 prior to installation that protects actuator 326 from premature actuation.

Referring next to FIGS. 5A-5B, therein is depicted a fluid flow control device according to the present invention that is representatively illustrated and generally designated 400. Fluid flow control device 400 includes a sand control screen section 402 and a flow restrictor section 404. Sand control screen section 402 includes a suitable sand control screen element or filter medium. In the illustrated embodiment, a protective outer shroud 406 having a plurality of perforations 408 is positioned around the exterior of the filter medium.

Flow restrictor section 404 is configured in series with sand control screen section 402 such that fluid must pass through sand control screen section 402 prior to entering flow restrictor section 404. Flow restrictor section 404 includes an outer housing 410. Outer housing 410 defines an annular chamber 412 and an annular chamber 414 with base pipe 418. Disposed at least partially within annular chamber 414 is a valve assembly 420. Valve assembly 420 includes a tubular fluid passageway 422, a support member 424, an actuator 426, a plunger 428 and a support member 430.

As best seen in FIG. 5A, tubular fluid passageway 422 serves as a flow restrictor to control fluid flow through fluid flow control device 400 when a desired fluid 434 is being produced. As illustrated, once desired fluid 434 enters flow restrictor section 404, desired fluid 434 passes through annular chamber 412 and encounters tubular fluid passageway 422 which restricts the flow of desired fluid 434. After passing through tubular fluid passageway 422, desired fluid 434 enters annular chamber 414 before passing into base pipe 418 via openings 436 for transport to the surface.

As best seen in FIG. 5B, when an undesired fluid 440 is produced, valve assembly 420 is actuated to its closed or choking position. In the illustrated embodiment, this actuation is achieved by longitudinally shifting plunger 428 such that it comes in contact with a seat in support member 424. Depending upon the sealing therebetween, this may result in a complete shut off of flow through fluid flow control device 400, as illustrated, or may result in an incomplete seal creating only an increased restriction to flow without completely preventing flow.

Actuator 426 is formed from a material that expands when it comes in contact with an activating agent. In an autonomous implementation of fluid flow control device 400, undesired fluid 440 serves as the activating agent. As best seen in FIG. 5B, once actuator 426 is exposed to the activating agent, actuator 426 swells to longitudinally shift plunger 428. Once this operation is complete, actuator 426 retains the activating fluid therein. As a result, after actuator 426 has transformed from its unswelled state (FIG. 5A) to its swelled state (FIG. 5B), actuator 426 retains its expanded size. If required, full access through fluid flow control device 400 can be reestablished via removal of plug 442. Alternatively, in certain embodiments, actuator 426 may be deactivated upon removal of the activating agent from contact with actuator 426. Alternatively or additionally, an outer skin may be applied to actuator 426 prior to installation that protects actuator 426 from premature actuation.

Depended upon the specific composition of the actuator, the swelling of the actuator may be related to the proportion of the undesired fluid in the production fluid stream. For example, using certain embodiments of the fluid flow control device of the present invention enables the progressive restriction of flow through the fluid flow control device as the proportion of water production increases. While the water cut is small, the material of the actuator may only swell a little such that the increase in the restriction to flow is only slight. As the water cut increase, the material of the actuator may increasingly swell, thereby creating a greater restriction to flow. Once the water proportion reaches a predetermined level, the material of actuator 426 swells to longitudinally shift plunger 428 such that it comes in contact with a seat in support member 424, as described above.

Referring next to FIGS. 6A-6B, therein is depicted a fluid flow control device according to the present invention that is representatively illustrated and generally designated 500. Fluid flow control device 500 includes a sand control screen section 502 and a flow restrictor section 504. Sand control screen section 502 includes a suitable sand control screen element or filter medium. In the illustrated embodiment, a protective outer shroud 506 having a plurality of perforations 508 is positioned around the exterior of the filter medium.

Flow restrictor section 504 is configured in series with sand control screen section 502 such that fluid must pass through sand control screen section 502 prior to entering flow restrictor section 504. Flow restrictor section 504 includes an outer housing 510. Outer housing 510 defines an annular chamber 512, an annular chamber 514 and an annular chamber 516 with base pipe 518. Disposed between annular chamber 512 and annular chamber 514 is a valve assembly 520. Valve assembly 520 includes a support member 524 and an actuator 526. Disposed between annular chamber 514 and annular chamber 516 is a tubular fluid passageway 522 and a support member 528.

As best seen in FIG. 6A, tubular fluid passageway 522 serves as a flow restrictor to control fluid flow through fluid flow control device 500 when a desired fluid 534 is being produced. As illustrated, once desired fluid 534 enters flow restrictor section 504, desired fluid 534 passes through annular chamber 512, valve assembly 520 and annular chamber 514 then encounters tubular fluid passageway 522 which restricts the flow of desired fluid 534. After passing through tubular fluid passageway 522, desired fluid 534 enters annular chamber 516 before passing into base pipe 518 via openings 536 for transport to the surface.

As best seen in FIG. 6B, when an undesired fluid 540 is produced, valve assembly 520 is actuated to its closed or choking position. In the illustrated embodiment, this actuation is achieved by radial expansion of actuator 526 which reduces the area of the flow path through valve assembly 520. Depending upon the extent of the radial expansion of actuator 526, this may result in a complete shut off of flow through fluid flow control device 500. In some instances a complete closedown of production is not wanted. In the illustrated embodiment, a relative small passageway exists within valve assembly 520. In this manner, the actuation of actuator 526 creates an increased restriction to flow, without completely preventing flow. Thus, some of unwanted fluid 540 is permitted to flow through valve assembly 520, annular chamber 514, tubular fluid passageway 522, annular chamber 516 and openings 536 into base pipe 518.

Actuator 526 is formed from a material that expands when it comes in contact with an activating agent. In an autonomous implementation of fluid flow control device 500, undesired fluid 540 serves as the activating agent. As best seen in FIG. 6B, once actuator 526 is exposed to the activating agent, actuator 526 swells to create a flow restriction. Once this operation is complete, actuator 526 retains the activating fluid therein. As a result, after actuator 526 has transformed from its unswelled state (FIG. 6A) to its swelled state (FIG. 6B), actuator 526 retains its expanded size. If required, full access through fluid flow control device 500 can be reestablished via removal of plug 542. Alternatively, in certain embodiments, actuator 526 may be deactivated upon removal of the activating agent from contact with actuator 526. Alternatively or additionally, an outer skin may be applied to actuator 526 prior to installation that protects actuator 526 from premature actuation.

As noted above, the fluid flow control devices of the present invention may have more that one valve assembly positioned in the flow restrictor section thereof. In the illustrated embodiment of FIGS. 6A-6B, it is particularly desirable to have multiple valve assemblies 520 as the valve assemblies can operate as fluid discriminators. Specifically, in certain flow conditions wherein the fluid being produced includes both the desired fluid and undesired fluid and wherein these component are stratified within fluid flow control device 500, valve assemblies 520 can operate independently of one another to preferentially reduce the production of the undesired fluid relative to the desired fluid. In the case of a production fluid containing both oil and water, stratification of this production fluid may result in the oil component being above the water component within annular chamber 512. As the water component is the activating agent to actuate valve members 520, only the valve members being exposed to the water, those to the bottom of fluid flow control device 500, will be actuated. This results in a preferential production of oil through the unactuated valve assemblies 520. Likewise, in the case of a production fluid containing both oil and gas, stratification of this production fluid results in the gas component being above the oil component within annular chamber 512. If the gas component is the activating agent to actuate valve members 520, only the valve members being exposed to the gas, those to the top of fluid flow control device 500, will be actuated. This results in a preferential production of oil through the unactuated valve assemblies 520.

Referring next to FIGS. 7A-7B, therein is depicted a fluid flow control device according to the present invention that is representatively illustrated and generally designated 600. Fluid flow control device 600 includes a sand control screen section 602 and a flow restrictor section 604. Sand control screen section 602 includes a suitable sand control screen element or filter medium. In the illustrated embodiment, a protective outer shroud 606 having a plurality of perforations 608 is positioned around the exterior of the filter medium.

Flow restrictor section 604 is configured in series with sand control screen section 602 such that fluid must pass through sand control screen section 602 prior to entering flow restrictor section 604. Flow restrictor section 604 includes an outer housing 610. Outer housing 610 defines an annular chamber 612 and an annular chamber 614 with base pipe 618. Disposed between annular chamber 612 and annular chamber 614 is a valve assembly 620. Valve assembly 620 includes a tubular fluid passageway 622, a support member 624 and an actuator 626.

As best seen in FIG. 7A, tubular fluid passageway 622 serves as a flow restrictor to control fluid flow through fluid flow control device 600 when a desired fluid 634 is being produced. As illustrated, once desired fluid 634 enters flow restrictor section 604, desired fluid 634 passes through tubular fluid passageway 622 which restricts the flow of desired fluid 634. After passing through tubular fluid passageway 622, desired fluid 634 enters annular chamber 614 before passing into base pipe 618 via openings 636 for transport to the surface.

As best seen in FIG. 7B, when an undesired fluid 640 is produced, valve assembly 620 is actuated to its closed or choking position. In the illustrated embodiment, this actuation is achieved by radial expansion of actuator 626 which radially compresses tubular fluid passageway 622 and reduces the area of the flow path through tubular fluid passageway 622. Depending upon the extent of the radial expansion of actuator 626, this may result in a complete shut off of flow through fluid flow control device 600. In some instances a complete closedown of production is not wanted. In the illustrated embodiment a relatively small passageway exists through tubular fluid passageway 622. In this manner, the actuation of actuator 626 creates an increased restriction to flow, without completely preventing flow. Thus, some of unwanted fluid 640 is permitted to flow through tubular fluid passageway 622 into annular chamber 614 through openings 636 into base pipe 618.

Actuator 626 is formed from a material that expands when it comes in contact with an activating agent. In an autonomous implementation of fluid flow control device 600, undesired fluid 640 serves as the activating agent. As best seen in FIG. 7B, once actuator 626 is exposed to the activating agent, actuator 626 swells to increase the flow restriction of tubular fluid passageway 622. Once this operation is complete, actuator 626 retains the activating fluid therein. As a result, after actuator 626 has transformed from its unswelled state (FIG. 7A) to its swelled state (FIG. 7B), actuator 626 retains its expanded size. If required, full access through fluid flow control device 600 can be reestablished via removal of plug 642. Alternatively, in certain embodiments, actuator 626 may be deactivated upon removal of the activating agent from contact with actuator 626. Alternatively or additionally, an outer skin may be applied to actuator 626 prior to installation that protects actuator 626 from premature actuation.

Referring next to FIGS. 8A-8B, therein is depicted a fluid flow control device according to the present invention that is representatively illustrated and generally designated 700. Fluid flow control device 700 includes a sand control screen section 702 and a flow restrictor section 704. Sand control screen section 702 includes a suitable sand control screen element or filter medium. In the illustrated embodiment, a protective outer shroud 706 having a plurality of perforations 708 is positioned around the exterior of the filter medium.

Flow restrictor section 704 is configured in series with sand control screen section 702 such that fluid must pass through sand control screen section 702 prior to entering flow restrictor section 704. Flow restrictor section 704 includes an outer housing 710. Outer housing 710 defines an annular chamber 712 and an annular chamber 714 with base pipe 718. Disposed at least partially within annular chamber 714 is a valve assembly 720. Valve assembly 720 includes a tubular fluid passageway 722, a support member 724, a sliding sleeve 728 and a support member 730. Valve assembly 720 also includes an actuation system including actuator 726 and biasing member 732.

As best seen in FIG. 8A, tubular fluid passageway 722 serves as a flow restrictor to control fluid flow through fluid flow control device 700 when a desired fluid 734 is being produced. As illustrated, once desired fluid 734 enters flow restrictor section 704, desired fluid 734 passes through annular chamber 712 and encounters tubular fluid passageway 722 which restricts the flow of desired fluid 734. After passing through tubular fluid passageway 722, desired fluid 734 enters the interior of sliding sleeve 728, passes through openings 736 into annular chamber 714 before passing into base pipe 718 via openings 738 for transport to the surface.

As best seen in FIG. 8B, when an undesired fluid 740 is produced, valve assembly 720 is actuated to its closed or choking position. In the illustrated embodiment, this actuation is achieved by longitudinally shifting sliding sleeve 728 such that openings 736 are blocked by the outer surface of the tubular including tubular fluid passageway 722. Depending upon the sealing therebetween, this may result in a complete shut off of flow through fluid flow control device 700. In some instances a complete closedown of production is not wanted. In the illustrated embodiment an incomplete seal is created between sliding sleeve 728 and tubular fluid passageway 722. In this manner, the actuation of actuator 726 creates an increased restriction to flow, without completely preventing flow. Thus, some of unwanted fluid 740 is permitted to flow through openings 738 into base pipe 718.

Actuator 726 is formed from a composite material that includes a plurality of pellets of a material that expands when it comes in contact with an activating agent in an epoxy matrix. In an autonomous implementation of fluid flow control device 700, undesired fluid 740 serves as the activating agent. As best seen in FIG. 8B, once actuator 726 is exposed to the activating agent, the swellable pellets of actuator 726 swell and break the epoxy matrix which allows the biasing force of biasing member 732 to longitudinally shift sliding sleeve 728. Once this operation is complete, full access through fluid flow control device 700 can be reestablished via removal of plug 742.

While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments. 

1. A sand control screen positionable within a wellbore, the sand control screen comprising: a base pipe having at least one opening that allows fluid flow between an exterior of the base pipe and an interior flow path of the base pipe; a filter medium positioned exteriorly of the base pipe, the filter medium selectively allowing fluid flow therethrough and preventing particulate flow of a predetermined size therethrough; and a flow restricting device operably positioned in a fluid flow path between the filter medium and the at least one opening, the flow restricting device including a valve and an actuator, the actuator including a material that swells in response to contact with an undesired fluid such that the flow restricting device is operable to autonomously reduce the fluid flow through the screen in response to contact between the material and the undesired fluid.
 2. The sand control screen as recited in claim 1 wherein the fluid flow through the screen is increasingly restricted in response to contact between the material and the undesired fluid.
 3. The sand control screen as recited in claim 1 wherein the fluid flow through the screen is substantially completely restricted in response to contact between the material and the undesired fluid.
 4. The sand control screen as recited in claim 1 wherein the undesired fluid is water.
 5. The sand control screen as recited in claim 1 wherein the undesired fluid is gas.
 6. The sand control screen as recited in claim 1 wherein the valve further comprises a sliding sleeve.
 7. The sand control screen as recited in claim 1 wherein the valve further comprises a longitudinally shiftable valve element.
 8. The sand control screen as recited in claim 1 wherein the valve further comprises a valve element having a fluid flow passageway with a cross sectional area that is reduced in response to contact between the material and the undesired fluid.
 9. The sand control screen as recited in claim 1 wherein the actuator further comprises a biasing member that biases a valve element in a first direction and wherein the material prevents movement of the valve element in the first direction until the material is contacted by the undesired fluid.
 10. The sand control screen as recited in claim 1 wherein the material remains in a swelled state as long as the material stays in contact with the undesired fluid and returns to an unswelled state when contact with the undesired fluid ceases.
 11. A flow control apparatus for controlling the inflow of production fluids from a subterranean well, the flow control apparatus comprising: a tubular member having at least one opening that allows fluid flow between an exterior of the tubular member and an interior flow path of the tubular member; and a flow restricting device operably positioned in a fluid flow path between a fluid source and the at least one opening, the flow restricting device including a valve and an actuator, the actuator including a material that swells in response to contact with an undesired fluid such that the flow restricting device is operable to autonomously reduce the fluid flow through the flow control apparatus in response to contact between the material and the undesired fluid.
 12. The flow control apparatus as recited in claim 11 wherein the fluid flow through the flow control apparatus is increasingly restricted in response to contact between the material and the undesired fluid.
 13. The flow control apparatus as recited in claim 11 wherein the fluid flow through the flow control apparatus is substantially completely restricted in response to contact between the material and the undesired fluid.
 14. The flow control apparatus as recited in claim 11 wherein the undesired fluid is water.
 15. The flow control apparatus as recited in claim 11 wherein the undesired fluid is gas.
 16. The flow control apparatus as recited in claim 11 wherein the valve further comprises a sliding sleeve.
 17. The flow control apparatus as recited in claim 11 wherein the valve further comprises a longitudinally shiftable valve element.
 18. The flow control apparatus as recited in claim 11 wherein the valve further comprises a valve element having a fluid flow passageway with a cross sectional area that is reduced in response to contact between the material and the undesired fluid.
 19. The flow control apparatus as recited in claim 11 wherein the actuator further comprises a biasing member that biases a valve element in a first direction and wherein the material prevents movement of the valve element in the first direction until the material is contacted by the undesired fluid.
 20. The flow control apparatus as recited in claim 11 wherein the material remains in a swelled state as long as the material stays in contact with the undesired fluid and returns to an unswelled state if contact with the undesired fluid ceases.
 21. A sand control completion for installation in a wellbore, the completion comprising: first and second seal assemblies that define a production zone in the wellbore; and a sand control screen operably positioned between the first and second seal assemblies, the sand control screen comprising a base pipe having at least one opening that allows fluid flow between an exterior of the base pipe and an interior flow path of the base pipe, a filter medium positioned exteriorly of the base pipe, the filter medium selectively allowing fluid flow therethrough and preventing particulate flow of a predetermined size therethrough and a flow restricting device operably positioned in a fluid flow path between the filter medium and the at least one opening, the flow restricting device including a valve and an actuator, the actuator including a material that swells in response to contact with an undesired fluid such that the flow restricting device is operable to autonomously reduce the fluid flow through from the production zone in response to contact between the material and the undesired fluid.
 22. A multizone sand control completion for installation in a wellbore, the completion comprising: at least two sets of first and second seal assemblies that define at least two production zones in the wellbore; and a sand control screen positioned between each of the first and second seal assemblies, each of the sand control screens comprising a base pipe having at least one opening that allows fluid flow between an exterior of the base pipe and an interior flow path of the base pipe, a filter medium positioned exteriorly of the base pipe, the filter medium selectively allowing fluid flow therethrough and preventing particulate flow of a predetermined size therethrough and a flow restricting device operably positioned in a fluid flow path between the filter medium and the at least one opening, the flow restricting device including a valve and an actuator, the actuator including a material that swells in response to contact with an undesired fluid such that each of the flow restricting devices is operable to autonomously reduce the fluid flow from a respective production zone in response to contact between the material and the undesired fluid. 